Radiation detectors for use with CT sensors include a detector with a scintillator placed on the light-incident surface of a semiconductor photodetecting element array such as a photodiode array. In such a radiation detector, when the radiation to be detected is made incident on the scintillator, such as X-rays, gamma rays, or charged particles, scintillation light is generated by the radiation in the scintillator. The scintillation light is then detected with the semiconductor photodetecting elements, thereby allowing the radiation to be detected.
The photodetecting element array is also provided with a signal processing element for processing a detected signal that is outputted from each photodetecting element. In this case, the photodetecting element and the signal processing element can be electrically connected therebetween using various types of wirings, or conduction paths provided in a wiring substrate (e.g., see Japanese Patent Application Laid-Open No. H8-330469).